scope:

The telecommunication industry is assessing the sunsetting of the Public Switched Telephone Network (PSTN) as the carriers plan to transition their networks to IP core networks, specifically those utilizing IP Multimedia Subsystem (IMS) architectures. This has implications on legacy emergency services that are based upon Time Division Multiplexing (TDM) technologies. As carriers migrate to IMS, there is value in considering how emergency services can be supported in that environment. This ATIS Standard provides an overview and operational considerations for ATIS-0500032. That standard applies Common IMS architecture concepts to NG9- 1-1 Service Architectures to encompass:

• Definition of an IMS-based NG9-1-1 Service Architecture that includes an IMS-based NG9-1-1 Emergency Services Network architecture, and a set of additional gateway functional elements adopted from the existing NENA i3 architecture to support the delivery of emergency calls to legacy and NG9-1- 1/i3 PSAPs.

• NG9-1-1 network deployment scenarios showing an IMS-based Next NG9-1-1 Service Architecture interconnecting with a variety of originating network and PSAP types and associated Stage 2/3 call flows.

Purpose

The purpose of this standard is to provide an overview of, and discuss operational and deployment topics related to, ATIS-0500032.

Application

This standard applies to the following entities:

• NG9-1-1 System Service Providers that support IMS-based emergency services network architectures.

• Originating network providers that interconnect to IMS-based emergency services networks.

• PSAPs (legacy or NG9-1-1) that receive calls from IMS-based emergency services networks.